The present invention relates to database systems, and in particular, managing data of multiple users in a manner that enables efficient exportation of the data.
Use of commercial off-the-shelf applications (xe2x80x9cpackaged applicationsxe2x80x9d) has proliferated. Companies are buying packaged applications instead of developing in house applications, avoiding the higher cost associated with developing their own in house applications. The kinds of packaged applications that may be purchased include applications for financial processing, manufacturing work-flow, human resources, and customer relationship management.
Not only are companies buying packaged applications, they are employing service companies to maintain the packaged applications and the computer systems upon which they run. One technique used by service companies to maintain and operate packaged applications is referred to as application hosting. A service company maintains applications for multiple companies on one or more computer systems, using the same computer infrastructure to run all the packaged applications. The term infrastructure refers to both hard components (e.g. computers), and software components, (e.g. operating systems and database systems). A xe2x80x9chost customerxe2x80x9d may access an application via, for example, the Internet, or an extended intranet. Application hosting can reduce the cost of managing applications because its allows companies to share the resources needed to run a packaged application, resources which include computer components, application experts, and computer administrative support personnel, all of which are needed to operate a packaged application.
One resource which may be shared is the database system. An application host may use a single database system to store data for multiple host customers. Use of a single database system reduces the need to operate a heterogeneous set of database systems, which may require the use of different database system software, hardware, and experts.
Eventually, the data of an application host customer may have to be moved to another database system. There may be a variety of reasons for moving the data. The host customer may simply wish to switch application hosts, may wish to operate their own application in-house, or the application host may simply be moving the data as part of a reconfiguration of the computer systems operated by the application host. With respect to a particular database system, the process of moving data to another database system is referred to as exporting.
A conventional technique for exporting data is the command generation technique. Under the command generation technique, the exporting database system generates a file of insert commands. The insert commands conform to a standard database language, such as structure query language (xe2x80x9cSQLxe2x80x9d). For each record being exported, an insert command specifies the creation of a record with the values needed to generate a copy of the record being exported. To import the data, another database, that is capable of executing commands written in the standard database language, scans the file, executing each insert command.
Executing an insert command for each record to export is typically a slow process, one which may for larger databases span days. While data is being exported, access to the data is restricted; consequently, the business operations of a customer host, which require access to the data, may be significantly impacted. Thus, conventional techniques for exporting data may significantly burden a host customer.
Based on the foregoing, it is clearly desirable to not only provide a mechanism that allows exporting data for a particular host customer to another database system, but to provide a mechanism for exporting data that is quicker and more efficient than conventional techniques, such as the command generation technique.
Described herein are mechanisms that may be used to support efficient exportation of user data stored in a database system. According to an aspect of the present invention, a database system is configured to store data for users in separate repositories referred to as tablespaces. To store data in this manner, a database system may be configured in variety of ways.